3.4. CTRP9 Alleviates ox-LDL-Induced VSMC-Derived Foam Cell Necroptosis
To clarify the potential role of CTRP9 in ox-LDL-induced necroptosis of VSMC-derived macrophage-like foam cells, we examined cell morphology using electron microscopy. VSMC-derived foam cells were either left untreated or treated with 10 μg/mL ox-LDL in the presence of different concentrations of CTRP9. With increasing CTRP9 concentration, the number of necroptotic cells decreased significantly, and the structure of the cell membrane and organelles became increasingly complete (Fig. 4a). In addition to altering cell morphology, CTRP9 reduced the proportion of PI-positive cells (Fig. 4b). Western blotting analysis revealed that ox-LDL promoted RIP1 and MLKL phosphorylation in VSMC-derived foam cells, whereas CTRP9 prevented this phosphorylation, and higher concentrations of CTRP9 further reduced the expression of necroptosis-related proteins (Fig. 4c and d). Thus, CTRP9 effectively protected VSMC-derived foam cells from ox-LDL-induced necroptosis. To further verify this finding, we measured the expression levels of cell phenotype markers, pro-atherosclerotic genes, and inflammatory factors using qRT-PCR and found that CTRP9 inhibited the expression of pro-atherosclerotic genes and inflammatory factors induced by ox-LDL in a dose-dependent manner (Fig. 4e).